Hot air furnace



G. A. TUCK HOT AIR FURNACE Nov.. 3, 1931 Fild sept.

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HOT AIR FURNAGE Filed Sept. 10, 1927 2 Sheets-Sheet 2 Nov. 3, 1931.

-u HW@ @\1 i@ Patented Nov. 3, 1931 i GEORGE A. TUCK, OF SAN FRANCISCO, CALIFORNIA HOT AIR rURNAoE Application filed September 10, 1927. SeralNo. 218,683.

burning furnace for warming air. An object of the invention is to provide' a furnace for warming air comprised of a plurality of connected heating compartments, having a relatively large external surface area, through which products of combustion pass in a substantially uniform flow of gradually decreasing temperature from the point 1Q of maximum temperature to the point of discharge of the products of combustion, and with which the air to be heated contacts, to raise the temperature thereof.4

This invention relates particularly to a gas A further object of theinvention is topro' vide an air heating device formedof a plurality ofconnected heating compartments,

having a primary heating compartment with an opening at. the lower end thereof, and a gas burner arranged relative to said opening to pass products of combustion into the initial compartment to render available all of theV heat units contained within the fuel, to pro.` vide an eiiicient combustion and to prevent the generation of toxic gases, such as carbonV monoxide and thelike'.

' Other objects of the invention are to pro-` vide a warm air furnace that will be superior in point of simplicity, inexpensiveness of operation, and facility and convenience in use and general efficiency. f

In this specification and the annexed drawings, the invention is illustrated in the form considered to be Vthe best, but it is to be understood that the invention is not limited to such form, because it may be embodied in vother forms, and it isalso to be understood that in and by the claims following the description, it is desired to cover the invention in whatsoever form it may be embodied.V i In the accompanying two sheets of drawings.

Fig. 1 represents a vertical cross section through a warm air heater constructed in accordance with my invention, taken on the -line 1-1 of Fig. 2.

Fi 2 isa plan view of the furnace shown inFigzl.; g' v r` Fig. 3 is a Vlongitudinal section taken through Fig. 2 on the line 3 3.

Fig. 4. is afront elevation' of the furnace,

Fig.` 5'is a plan View from the inside of the burner draftgates.

In detail, the construction illustrated in the drawings comprises a furnace housing 1, having a screened air inlet 2 on the rear side 65 thereof and arwarm. air outlet 3, in the center of a cover l closing the top thereof. A casing 5 that has its opposite ends open, is suspended within the housing 1 from the-cover" 4, whereby the open upper end of the casing ou 5 registersv with the outlet 3V in the housing top; .Thelo'werend of the casing 5 issupportedabove the ground surface, on whichV the housing 1 rests, but belowthe level of the air inlet 2 whereby anyair entering thehous- 66 1 ing l to be heated'must pass downwardly and under the open bottom end of the casing 5 before it can flow upwardly and out through the outlet 3. I A y' VWithin the casing 5, I have mounted a plu-` 'mi rality'of heating compartments. In the present drawings, I have shown three, substany tially rectangular and upright heating com-f partments lying in parallel relation to each other, andconsisting of the primary heating nix chamber 6,1the secondary heating chamber 7 and the tertiary heating chamber 8.y The heating compartments 6, 7 and 8 are con` lined within the casing 5, in a baffled arrangement so as to occupy substantially theV entire area thereof, and hence make it necessary for any air passing through the casing 5 to come in contact with someportion of the outside of one of the heating compartments.

The primary combustion chamber 6 is pro- 85? vided with an elongated opening 9 at the bottom end thereof for the admission of the products of combustion and atmosphericair into the primary heating chamber. A gas burner 10 extends transversely across the "1 lower end of the primary heating chamber, in relation to the opening 9 on the bottom thereof, and said burner has a set of apertures 11 arranged yalong its upper sideV fromV whichthe combustible mixture may issue-and pro-V 951? vide heaty and flames Vwhich can impinge against the 'sides of-a frame 12 bounding the opening 9 within the interior of the lower end of the primary heating chamber and forming 1 a ycombustion chamber therein. The frame We 12 forming the combustion chamber is spaced from the walls of the primary heating chamber whereby said chamber walls are protected against being burned out and hence minimizing the possibility of the products of combustion commingling with the air to be heated. The combustion chamber 12 guides the heated products of combustion from the burner upwardly within the interior of the primary heating chamber and properly distributes the products of combustion, whereby the temperature throughout the said compartment is made substantially uniform. The burner 10 has a primary air control inlet 13 and gas supply pipe 14 controlled by a valve 15, for the admission of natural or manufactured gas, to be mixed with air and liberated through the openings in the burner 10, whereby it may be conveniently ignited by a lighted match or taper. A door 16 is provided in the front of the furnace to permit access to the burner. Burners of this type consume natural gas made from oil or coal or other carbon and give off a clear blue smokeless flame, which may contain noxious elements. In order to have a perfect combustion and to render the products of combustion from the burner harmless, I provide a pair of adjustable draft gates 17 and 18 on opposite sides of the inlet 9 into the primary heating chamber, which may be regulated to control the volume of secondary fresh air passing into the heating chamber, in combination with the products of combustion, to prevent the generation of carbon monoxide or other toxic gases. The secondary air that passes into the combustion chamber 12 commingles andinixes with the flames of the burner and hence causes a complete combustion of all the fuel issued from the burner. The means to regulate the supply of secondary air to the combustible mixture thus controls the leanness or heavinessA of the said mixture.

The products of combustion pass upwardly, through the inlet 9 within the primary combustion chamber 6, and outwardly through a plurality of conduits 19, adjacent the upper end thereof, which said conduits communicate with the upper end of the secondary heating compartment 7. The com bined cross sectional area of all of the communicating conduits 19 is less than the cross sectional area of the primary heating compartment 6, whereby the said products of combustion will be partially backed up within the primary heating chamber to uniformly distribute the temperature of the products of combustion within the chamber 6 before the said products pass into the secondary heating chamber 7. I have found by spacing apart the plurality of conduits 19 as well as the similar conduits connecting all of the chambers, brings about a more uniform distribution and connningling of the products of combustion, so that there is no appreciable dierence in temperature of the products of combustion throughout each and every heating compartment. The products of combustion that enter the secondary heating chamber 7, pass downwardly therein and are partially backed up before passing outwardly through a plurality of spaced conduits 20, arranged along the bottom side thereof, into the lower end of the tertiary heating chamber 8. The products of combustion that enter the lower end of the tertiary chamber 8 rise to the upper end 21 thereof (in thoroughly intermixed relation) across the end of which I have arranged a plurality of independent conduits 22. Each of the conduits 22, communicate with-a flue 23. The conduits 22 hold the products of combustion within the tertiary chamber 8 and restrain the flow thereof into the flue 23, whereby the products of combustion within said compartment 8 are uniformly distributed and the temperature thereof is substantially the same throughout. A stack pipe 24 of lesser diameter than that of the flue 23 is connected to one end thereof to retard the liow of the products of combustion from the fine 23 outwardly into the stack. The temperature of the products of combustion entering the stach will be low enough to not reduce the draft efliciency of the stack and yet not high enough that heat units in the products of combustion will be wasted by being exhausted out of the stack. The spaced relationship of the conduits connecting each of the various heating chambers prevents a stratifying of the products of combustion into different temperatures within each heating chamber, whereby one side of a heating compartment might be of a different temperature than an opposite side, but brings about a uniformity of tem ierature in each chamber.

rlhe invention operates in the following manner. The heat from the flame, and the products of combustion from the burner 10 enter the primary heating compartment 6 and draw a .restricted Volume of secondary air through the inlet 9 in the bottom of the combustion chamber 12, past the draft gates 17 and 18 thereon, and rises and min gles with the products of combustion, causing a rarefaction of air within the heating chambers that eventually causes a circulation of the products of combustion from the primary heating compartment into the secondary and tertiary heating compartments, and finally out through the stack. The temperature of the products of combustion gradually decreases from the primary heating compartment to the tertiary heating compartment. The conduits communicating each of the various compartments, as well as the conduits which communicate the flue with the tertiary compartment, are so proportioned, in respect to the various compartments, that by the time the products of combustion have passed @asados through all of said compartments, the maxi'- Vmum of the heat units will have been absorbed therefrom and thetemperature of said products of combustion materially reduced by the air that is being warmed coming into contact with the outside of the various heating compartments.

The various housings and casings as well as the heating compartments, are all constructed in accordance with the usual practice in the sheet metal art; wherein the various parts of the apparatus may be assembled in the shop and later taken down for transportation to the point where the furnace is to be set up in use.

Having thus described this invention, what I claim and desire to secure by Letters Patent is:

l. An air heating device comprising a casing having an independent air inlet and air outlet therein; an air heater in said casing between the air'inlet and air outlet, having a, vertically disposed primary heating chamber provided at its lower end with an air inlet; a burner extended across the lower end of the chamber; a secondary heating chamber connected to the Vupper end of the primary chamber by restricted conduits arranged across the width of said chamber; a vertically disposed tertiary heating chamberconnected at its lower end to the lowerv end of the secondary heat-y ing chamber by restricted conduits; and a horizontally disposed draft chamber for exeh hausting the. products of combustion, communicating with the upper end of the tertiary chamber through restricted conduits, therestricted conduits;A at the respective ends of the secondary chamber being so proportioned that the total area of the respective end conduits is less'than the cross sectional area of the respective 'heating chambers so as to allow the building up ofA uniform pressure in said chambers. f

2. An air heating device comprising a casing having an independent air inlet and air outlet therein; an air heater in said casing between the aforementioned inlet and outlet consisting of a. plurality of vertically disposed heating chambers, each connected to the other at opposite ends thereof by a plurality of conduits arranged across the width of each chamber having a combined crosssectional area less than the cross sectional area of any one of the heating chambers. the endmost chambers having ports therein; a burner extended across the lower end of one of the heating chambers having an air port therein; and a horizontally Vdisposed draft chamber, for exhausting the products of combustion thatpass through the connected heating chambers connected to the port in the upper end of one of the heating chambers furthest from the heating chamber having the burner therein; the restricted c0nduits at the respective ends of the secondary chamber being so proportioned that the total area of the respective end conduits is less than the cross sectional area of the respective heating chambers so as `to allow the 4building up of uniform pressure in said chambers. v y i 3. An air heating 'device comprising a casing having anA independent air inlet and air outlet therein; an air heater in said casingbetween the air inlet and air outlet having a primary vertically disposed heating chamber provided at its lower end with a horizontally disposed air-inlet; afvrame bounding theedges of the air inlet within the chamber; a burner extended across the air inlet and having apertures therein arranged on its longitudinal axis for providing Haines which will thoroughly intermix with the air to forma combustible mixture in the frame in the primary chamber;` a vertically disposed secondary heating chamber connected to the upper end of the primary chamber by restricted conduits arranged across the widt-hof'said`chamber; a vertically disposed tertiary heating chamber connected at its lowerrend to the lower end of the secondary heating chamber by restricted conduits arranged across 'the width of said chamber; and a horizontally disposed draft chamber, for exhausting the products of combustion in communication with the upper end of the tertiary chamber, through restricted conduits arranged across the width of said chamber, the restricted conduits'at the respective ends of the secondary chamber being so proportioned that the total area. of the respective end conduits is less than the cross sectional area of the respective heating chambersl so as to allow the Vbuilding up of uniform pressure .in said chambers.

4. An air heating device comprising a cas ing having an independent air inlet and air outlet therein; an air heater in said casing between'the air inlet and air outlet having a vertically disposed primary heating cham ber providedat its lower end with an air inlet; means to regulate the volume of air passing through saidinlet; a frame bounding the edgesof the air inlet within the chamber; a burner extended across the air inlet and having apertures therein arranged on its longitudinal axis for providing fiames which will thoroughly intermix with the air to ,form a combustible mixture in the frame in the primary chamber; Aa vertically disposed secondary heating chamber'connected to the upper end of the primaryy chamber by restricted conduits arranged 4across the width of said chamber; a vertically disposed tertiary heating chamber connected at its lower end to the lower endof the secondary heating chamber by restricted conduits arranged across the width of said chamber;

and a horizontally disposed exhausting chamber"for the products of combustion communi` oat-ing with the upper eutl ot the tertiary chamber through restricted conduits arranged across the width of said chamber, the urestricted conduits at the respective ends of the secondary chamber being so proportioned that the total area of the respective end conduits is less than the cross sectional area of the respective heating chambers so as to allow the building up of uniform pressure in said chambers.

5. A heater of the character described, comprising vertically disposed primary, secondary and tertiary heating chambers, the primary and secondary chambers being in communication with each other by conduits arranged across the width of said chamber capable of diminishing the volume of air flow therebetween and the secondary and tertiary chambers being in communication with each other by conduits arranged across the width of said chamber capable of diminishingl the volume of air flow therebetween, said primary heating chamber having a horizontally disposed air inlet at the lower end thereof; a frame bounding the edges of the air inlet within the chamber; a burner eX- tended across the air inlet and having apertures therein arranged on its longitudinal axis for providingdames which will thoroughly inter-mix with the air to form a combustible mixture in the frame in the primary chamber; a horizontally disposed draft chamber connected to the upper end of the tertiary chamber by conduits arranged across the width of said chamber capable of diminishing the volume of air flow from the tertiary chamber into the flue,- to exhaust the heated air from the tertiary chamber; and a casing enclosing all of the heating chambers having an inlet therein through which air to be heated is passed into contact with the outside of the heating chambers, and an outlet through which heated air is drawn from the casing. said conduit-s being so proportioned that the total area of the conduits at the respective ends of the secondary chamber is less than the cross sectional area of the respective chambers to allow the building up of uniform pressure in said chambers.

6. A heater of the character described, comprising vertically disposed primary, secondary and tertiary heating` chambers, the primary and secondary chambers being in communication with each other adjacent the top thereof by conduits arranged across the width of said chamber capable of diminishing the volume of air flow therebetween and the secondary and tertiary chambers being in communication with each other adjacent the bottom thereof by conduits arranged across the width of said chamber capable of diminishing the volume of air flow therebetween., said primary heating chamber having a horizontally disposed air inlet at the lower end therof; means to regulate the voltime of uir passing through said inlet; a

frame bounding the edgesof the air inlet within the chamber; a burner extended across the air inlet and having apertures therein arranged on its longitudinal axis for providing flames which will thoroughly intermiX with the air to form a combustible mixture in the frame in the primary chamber; a horizontally disposed draft chamber, connected to the upper end of the tertiary chamber by conduits arranged across the width of said chamber capable of diminishing the volume of air flow from the tertiary chamber into the flue, to exhaust the heated air from the tertiary chamber; and a casing enclosing all of the heating chambers having an inlet therein through which air to be heated is passed into contact with the outside of the heating chambers, and an outlet through which heated air is drawn from the casing, said conduits being so proportioned that the total area of the conduits at the respective ends of the secondary chamber is less than the cross sectional area of the respective chambers to allow the building up of uniform pressure in said chambers.

7. A heater of the character described coniprising a plurality of independent compartments; conduits communicating adjacent ends of contiguous compartments, one compartment being communicated with an adjacent compartment at one end thereof and with an independent adjacent compartment at an opposite end thereof, each of said sets of conduits having a combined volumetric capacity less than that of each of the compartments to which they are connected; a burner arranged across an inlet in the lower end of one of the compartments distant from the conduits in the same compartment; a draft chamber arranged adjacent an end of the compartment furthermost from the compartment having the burner therein; and conduits, communicating the draft chamber and last mentioned compartment, distant from the conduits in the same compartment, said chamber conduits having a combined volumetric capacity less than that ofthe compartment to which they are related.

8. A heater of the character described comprising a plurality of independent compartments; conduits communicating adjacent ends of contiguous compartments, one compartment being communicated with an adjacent compartment at one end thereof and with an independent adjacent compartment at an opposite end thereof, each of said sets of conduits having a combined volumetric capacity less than that of each of the compartments to which they are connected; a burner arranged across an inlet in the lower end of `one of the compartments distant from the conduits inthe same compartment; means to regulate the air flow into the compartment past the burner; a draft chamber arranged adjacent an end of the compartment furthermost from the compartment having the burner therein; and conduits communicating the draft chamberand last mentioned compartment, distant from the conduits in the same compartment, saidV draft Vchamber conduits having a combined volumetric capacity less than that of the compartment to Which they are related.

9. A heater of the character described comprising a plurality of independent compartments; conduits communicating adjacent ends of contiguous compartments, one com.

partment being communicated With an adj acentJ compartment at one end thereof and with an independent adjacent compartment at an opposite end thereof; each of said sets of conduits having a combined volumetric capacity less than that of each of the compartments to which they are connected; a burner arranged across an inlet in the loWer end of one of the compartments distant from the conduits in the same compartment; a draft chamber arranged adjacent an end of the compartment furthermost from the compartment having the burner therein; conduits, communicating the draft chamber and last mentioned compartment, distant from the conduits in the same compartment, said draft chamber conduits having a combined volumetric capacity less than that of the compartment to which they are related; and a casing, enclosing all of the heating compartments, having an inlet therein through Which air to be heated is passed into contact with the outside of the heating compartments and an outlet through which heated air is drawn from the casing.

10. A heater of the character described comprising a plurality of independent compartments; conduits communicating adjacent ends of contiguous compartments, one compartment being communicated with an adjacent compartment at one end thereof1 and with an independent adjacent compartment at an opposite end thereof, each of said sets of conduits having a combined volumetric capacity less than that of each of the compartments to which they are connected; a burner arranged across an inlet in the lower end of one of the compartments distant from the conduits in the same compartment; means to regulate the air flow into the compartment past the burner; a draft chamber arranged adjacent an end of the compartment furthermost from the compartment having the burner therein; conduits, communicating the draft chamber and last mentioned compartment, distant from the conduits in the same compartment, said chamber conduits having a combined volumetric capacity less than that of the compartment to which they are related; and a casing, enclosing all of the heating compartments, having an inlet therein through VWhich air to be heated is passed 

